Drawbar assembly for motor grader

ABSTRACT

A drawbar assembly for a motor grader is provided. The drawbar assembly includes a yoke plate, a backbar, a drawbar tube, and a sleeve. The yoke plate includes a first surface and a second surface. The backbar is attached to the first surface of the yoke plate. The backbar includes a tube facing surface. The drawbar tube includes a first end and a second end. The drawbar tube is attached to the first surface of the yoke plate, defining a clearance between the first end of the drawbar tube and the tube facing surface of the backbar. The sleeve encloses at least a portion of the drawbar tube. The sleeve includes a backbar attachment portion and a yoke attachment portion. The backbar attachment portion is attached to the tube facing surface of the backbar and the yoke attachment portion is attached to the first surface of the yoke plate.

TECHNICAL FIELD

The present disclosure generally relates to a drawbar assembly for a motor grader.

BACKGROUND

Machines, such as motor graders, are commonly used in earth levelling applications, such as road maintenance and surface contouring. A motor grader generally employs a drawbar assembly installed on a main frame of the motor grader. The drawbar assembly supports a blade, which performs earth levelling during normal operation of the motor grader. Typically, the drawbar assembly includes a yoke plate, a backbar, and a pair of drawbar tubes. The backbar is attached to the yoke plate and extends vertically from the yoke plate. Each of the drawbar tubes is fixedly attached to the yoke plate. Each of the drawbar tubes includes a first end and a second end. The first end of each of the drawbar tubes is fixedly attached to the main frame. The second end of each of the drawbar tubes is fixedly attached to the backbar.

Conventionally, the motor grader has an increased weight for various load bearing requirements of the motor grader. Due to the increased weight of the motor grader, various components of the drawbar assembly may undergo an increased amount of stress. Moreover, as each of the drawbar tubes is relatively thinner than the backbar, an attachment between each of the drawbar tubes and the backbar may primarily experience the increased amount of stress.

U.S. Patent Application Number 2015/0008296 (hereinafter referred as the '296 reference) describes a drawbar assembly including a backbar, a pair of drawbar tubes, and a number of cylinder connection devices. In the '296 reference, one end of each of the drawbar tubes is fixedly attached to the backbar. An attachment between each of the first drawbar tube, the second drawbar tube and the backbar undergoes the increased amount of stress.

In these machines, increased stress may be experienced by the drawbar assembly, leading to a reduced work life of the drawbar assembly. This may also lead to an increased downtime and operating cost of the motor grader, which in turn may reduce overall productivity of the motor grader. Hence, there is a need for an improved design for the drawbar assembly.

SUMMARY OF THE DISCLOSURE

Various aspects of the present disclosure describe a drawbar assembly for a motor grader. The drawbar assembly includes a yoke plate, a backbar, a drawbar tube, and a sleeve. The yoke plate includes a first surface and a second surface. The backbar is attached to the first surface of the yoke plate. The backbar includes a tube facing surface. The drawbar tube includes a first end and a second end. The drawbar tube is attached to the first surface of the yoke plate, defining a clearance between the second end of the drawbar tube and the tube facing surface of the backbar. The sleeve encloses a portion of the drawbar tube. The sleeve includes a backbar attachment portion and a yoke attachment portion. The backbar attachment portion is attached to the tube facing surface of the backbar and the yoke attachment portion is attached to the first surface of the yoke plate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a motor grader, in accordance with the concepts of the present disclosure;

FIG. 2 is a perspective view of a drawbar assembly of the motor grader of FIG. 1, in accordance with the concepts of the present disclosure;

FIG. 3 is a perspective view of a first sleeve of the drawbar assembly, in accordance with the concepts of the present disclosure; and

FIG. 4 is a perspective view of an alternate embodiment of the first sleeve of the drawbar assembly, in accordance with the concepts of the present disclosure.

DETAILED DESCRIPTION

Referring to FIG. 1, a side view of an exemplary machine 10 is illustrated. The machine 10 is a motor grader 10. The motor grader 10 is employed to perform earth levelling operation on a work surface (not shown). The motor grader 10 includes a main frame 12, a number of wheels 14, a cab 16, a power unit 18, a blade assembly 20, and a drawbar assembly 22.

The main frame 12 is supported on the wheels 14, which facilitates machine maneuvering. The main frame 12 supports various components of the motor grader 10. The main frame 12 includes a first frame member 24 and a second frame member 26. The first frame member 24 is positioned proximal to a rear end 28 of the motor grader 10. The first frame member 24 supports the power unit 18 of the motor grader 10. The second frame member 26 is an elongated member rotatably attached to the first frame member 24 of the main frame 12. The second frame member 26 is positioned proximal to a frontal end 30 of the motor grader 10. The second frame member 26 supports the cab 16 of the motor grader 10. Additionally, the second frame member 26 supports the drawbar assembly 22, which in turn, supports the blade assembly 20 of the motor grader 10.

The blade assembly 20 includes a blade 32 that performs levelling operation on the work surface (not shown). The blade 32 is supported on the drawbar assembly 22, via a number of support members 34. The drawbar assembly 22 is employed to adjust an orientation of the blade 32, when required. Structure and arrangement of the drawbar assembly 22 will now be discussed in detail.

The drawbar assembly 22 is suspended from the second frame member 26 and is positioned beneath the second frame member 26. The drawbar assembly 22 includes a first end portion 36 and a second end portion 38. The first end portion 36 of the drawbar assembly 22 is coupled to a front section 40 of the second frame member 26. A universal coupling (not shown) is generally employed to couple the first end portion 36 to the front section 40 of the second frame member 26. Although, the universal coupling (not shown) is described in the present disclosure, various other coupling means to couple the first end portion 36 with the front section 40 of the second frame member 26 may also be contemplated.

The second end portion 38 of the drawbar assembly 22 is suspended from the second frame member 26, via two control actuators 42 (one on each side of the motor grader 10). More specifically, one end of each control actuator 42 is fixedly attached to the second frame member 26 and other end of each control actuator 42 is coupled to the drawbar assembly 22. Additionally, a center shift actuator 43 is positioned between the second frame member 26 and the drawbar assembly 22, to horizontally adjust the drawbar assembly 22 when required. The drawbar assembly 22 supports the blade assembly 20 between the first end portion 36 and the second end portion 38.

Referring to FIG. 2, the drawbar assembly 22 includes a yoke plate 44, a backbar 46, a first drawbar tube 48, a second drawbar tube 50, a first sleeve 52, and a second sleeve 54. The yoke plate 44 provides a mounting base for various other components of the drawbar assembly 22. The yoke plate 44 includes a first surface 56 and a second surface 58. The first surface 56 of the yoke plate 44 faces the second frame member 26. The second surface 58 of the yoke plate 44 faces the blade assembly 20 (see FIG. 1).

The backbar 46 is installed on the second end portion 38 of the drawbar assembly 22. The backbar 46 includes a plate attachment surface 60 and a tube facing surface 62. The plate attachment surface 60 of the backbar 46 is fixedly attached to the first surface 56 of the yoke plate 44, such that the backbar 46 extends vertically away from the first surface 56 of the yoke plate 44. An attachment means between the plate attachment surface 60 and the first surface 56 includes, but is not limited to, an electro-fused attachment, a weld attachment, an adhesive attachment, a soldered attachment, a bolt attachment, and a rivet attachment. The tube facing surface 62 faces the first drawbar tube 48 and the second drawbar tube 50 of the drawbar assembly 22. Additionally, the backbar 46 defines a first end section 64 and a second end section 66. Each of the first end section 64 and the second end section 66 includes an actuator mounting section 68. Each control actuator 42 (see FIG. 1) is coupled to the backbar 46 of the drawbar assembly 22 at each actuator mounting section 68 of the first end section 64 and the second end section 66. In an embodiment, each control actuator 42 is coupled to each actuator mounting section 68 of the first end section 64 and the second end section 66, by a ball and stud arrangement.

The first drawbar tube 48 and the second drawbar tube 50 merge together to form a V-shaped section on the yoke plate 44. More specifically, each of the first drawbar tube 48 and the second drawbar tube 50 includes a first end 70, 72, a second end 74, 76, and a bottom portion 78, 80, respectively. More specifically, the first ends 70, 72 of the first drawbar tube 48 and the second drawbar tube 50 are adjoined together, at the first end portion 36 of the drawbar assembly 22. The second ends 74, 76 of the first drawbar tube 48 and the second drawbar tube 50 respectively are spaced apart from each other, at the second end portion 38 (see FIG. 1) of the drawbar assembly 22. Further, the bottom portions 78, 80 of the first drawbar tube 48 and the second drawbar tube 50 are attached to the first surface 56 of the yoke plate 44. The bottom portions 78, 80 are attached to the first surface 56, such that a clearance (not shown) is defined between the second ends 74, 76 and the tube facing surface 62 of the backbar 46. For example, the clearance (not shown) of 4 mm is defined between the second ends 74, 76 and the tube facing surface 62 of the backbar 46. An attachment means between the bottom portions 78, 80 and the first surface 56 includes, but is not limited to, a weld attachment, an adhesive attachment, a bolt attachment, and a rivet attachment.

The first sleeve 52 and the second sleeve 54 enclose a portion of the first drawbar tube 48 and the second drawbar tube 50, respectively. For ease in reference and understanding, a structure and arrangement of the first sleeve 52 relative to the first drawbar tube 48 will be explained in detail hereinafter. However, similar structure and arrangement of the second sleeve 54 relative to the second drawbar tube 50 may also be contemplated.

Referring to FIG. 3, the first sleeve 52 is a U-shaped structure that encloses the portion of the first drawbar tube 48 (see FIG. 2), proximal to the second end 74 (see FIG. 2) of the first sleeve 52. The first sleeve 52 is relatively thicker than the first drawbar tube 48. In an embodiment, the first sleeve 52 is formed from a single plate suitably bent to form the U-shaped structure. The first sleeve 52 includes a first side portion 86, a second side portion 88, and a top portion 90. Each of the first side portion 86 and the second side portion 88 includes a bottom surface, which in turn defines a yoke attachment portion 82 of the first sleeve 52. The first side portion 86 and the second side portion 88, in conjunction with the top portion 90, define a bar attachment portion 84 of the first sleeve 52. More specifically, the bar attachment portion 84 is an end face of the first sleeve 52, formed from each of the first side portion 86, the second side portion 88, and the top portion 90 of the first sleeve 52. The yoke attachment portions 82 are fixedly attached to the first surface 56 of the yoke plate 44. Referring to FIGS. 2 and 3, the bar attachment portion 84 is fixedly attached to the tube facing surface 62 of the backbar 46. With such arrangement, the first sleeve 52 encloses the portion of the first drawbar tube 48, proximal to the second end 74 of the first sleeve 52. An attachment means between the bar attachment portion 84 and the tube facing surface 62 may include, but is not limited to, a weld attachment, an adhesive attachment, a bolt attachment, and a rivet attachment. Similar attachment means between the yoke attachment portions 82 and the first surface 56 of the yoke plate 44, may also be contemplated.

Referring to FIG. 4 an alternate embodiment of a first sleeve 92 is illustrated. The first sleeve 92 is formed from three individual plates, namely a first side plate 98, a second side plate 100, and a top plate 102. Each of the first side plate 98 and the second side plate 100 is attached to the top plate 102, to form a U-shaped cross section. The first side plate 98 and the second side plate 100 define two yoke attachment portions 94 of the first sleeve 92. The first side plate 98 and the second side plate 100, in conjunction with the top plate 102 define a bar attachment portion 96 of the first sleeve 92. Referring to FIGS. 2 and 4, the yoke attachment portions 82, 94 are fixedly attached to the first surface 56 of the yoke plate 44 and the bar attachment portion 84, 96 is attached to the tube facing surface 62 of the backbar 46, to cover the second end 74 of the first drawbar tube 48. In an embodiment, the second sleeve 54 may be contemplated to possess similar structure and arrangement as that of the alternate embodiment of the first sleeve 92.

INDUSTRIAL APPLICABILITY

In operation, the drawbar assembly 22 is employed to support the blade assembly 20 of the motor grader 10. The drawbar assembly 22 includes the yoke plate 44, the backbar 46, the first drawbar tube 48, the second drawbar tube 50, the first sleeve 52, 92, and the second sleeve 54. The backbar 46 is attached to the first surface 56 of the yoke plate 44, extending vertically away from the first surface 56 of the yoke plate 44. The bottom portions 78, 80 of the first drawbar tube 48 and the second drawbar tube 50 are attached to the first surface 56 of the yoke plate 44, such that, the clearance (not shown) is defined between the second ends 74, 76 and the tube facing surface 62 of the backbar 46.

Furthermore, the first sleeve 52, 92, and the second sleeve 54 are provided to cover the portion of the first drawbar tube 48 and the second drawbar tube 50, respectively. For ease in reference and understanding, structure and arrangement of the first sleeve 52, 92 relative to the first drawbar tube 48 will be explained in details hereinafter. Similar structure and arrangement of the second sleeve 54 relative to the second drawbar tube 50 may also be contemplated. The first sleeve 52, 92 encloses the portion of the first drawbar tube 48, such that the bar attachment portion 84, 96 is attached to the tube facing surface 62 of the backbar 46 and the yoke attachment portions 82, 94 is attached to the first surface 56 of the yoke plate 44.

With such arrangement of the drawbar assembly 22, the load is transferred from the first drawbar tube 48 to the backbar 46, via the first sleeve 52, 92. Consequently, the first drawbar tube 48 may be precluded from stress corresponding to the increased load. Moreover, as the first sleeve 52, 92 is relatively thicker than the backbar 46, the increased load may be uniformly distributed on the first sleeve 52, 92. Therefore, the first sleeve 52, 92 may undergo relatively less stress. Hence, work life of the first drawbar tube 48 may be improved. Similar to the first sleeve 52, 92, the second sleeve 54 may enhance the work life of the second drawbar tube 50. Therefore, the disclosed drawbar assembly 22 may enhance the work life of the first drawbar tube 48 and the second drawbar tube 50. This, in turn, may correspond to relatively lower service costs and relatively less repair time.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of the disclosure. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof. 

What is claimed is:
 1. A drawbar assembly for a motor grader, the drawbar assembly comprising: a yoke plate including a first surface and a second surface; a backbar attached to the first surface of the yoke plate, the backbar including a tube facing surface; a drawbar tube including a first end and a second end, wherein the drawbar tube is attached to the first surface of the yoke plate, and wherein a clearance is defined between the second end of the drawbar tube and the tube facing surface of the backbar; and a sleeve adapted to enclose at least a portion of the drawbar tube, the sleeve including a backbar attachment portion and a yoke attachment portion, wherein the backbar attachment portion is attached to the tube facing surface of the backbar and the yoke attachment portion is attached to the first surface of the yoke plate. 